低能强流高电荷态离子加速器RFQ真空系统设计

Design of RFQ Vacuum System for Low Energy Intense-Highly-Charged Ion Accelerator Facility

81.25 MHz射频四极加速器(RFQ)是低能量强流高电荷态离子加速器装置(LEAF)的关键设备,为保障RFQ加速器的稳定运行和高质量出束,要求RFQ腔体达到10-6 Pa的超高真空环境。本文采用二级分子泵方案完成了LEAF RFQ的真空系统设计,详细介绍了真空系统设计及设备选型流程,并使用VAKTRAK和MOLFLOW+软件分别对设计方案进行了模拟计算。目前,LEAF RFQ平稳高效运行,实际测量真空度在1.4×10^(-6)Pa左右,满足供束和实验的要求。本工作验证了VAKTRAK和MOLFLOW+计算结果的可靠性,为强流重离子加速器装置(HIAF)真空系统设计积累了经验。

The 81.25 MHz radio frequency quadrupole(RFQ)accelerator is the key equipment of low energy intense-highly-charged ion accelerator facility(LEAF).In order to ensure the RFQ can achieve a stable operation and high-quality beam supply,the RFQ cavity vacuum is required to reach an ultra-high vacuum of about 10-6 Pa.In this paper,the design of the vacuum system of LEAF RFQ is completed by the two-stage molecular pump scheme,and the process of vacuum system design and equipment selection are introduced in detail.In addition,VAKTRAK and MOLFLOW+were used to simulate the vacuum distribution under the design scheme.At present,LEAF RFQ operates stably and efficiently,and the measured vacuum is about 1.4×10^(-6)Pa,which meets the requirements of beam supply and experiments.This work verifies the reliability of VAKTRAK and MOLFLOW+results and accumulates experience for vacuum system design of high intensity heavy-ion accelerator facility(HIAF).